Magnet unit and magnetron sputtering apparatus

ABSTRACT

A magnet unit has a first magnet element and a second magnet element. The first magnet element includes a first magnet which is provided to stand upright on a yoke plate, a second magnet which is provided to stand upright on the yoke plate and has a magnetic pole unlike the first magnet, and a third magnet which is provided with a tilt between the first magnet and the second magnet. The second magnet element includes a fourth magnet which is provided to stand upright on the yoke plate, a fifth magnet which is arranged to stand upright on the yoke plate and has a magnetic pole unlike the fourth magnet, and a sixth magnet which is provided with a tilt between the fourth magnet and the fifth magnet. The first magnet element and the second magnet element are alternately arranged in an endless shape.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a magnet unit and a magnetronsputtering apparatus and, more particularly, to an improvement in thestructure of a magnet unit arranged on the rear surface side of acathode electrode supporting a sputtering target and a magnetronsputtering apparatus having the magnet unit.

2. Description of the Related Art

A sputtering process used in deposition in the semiconductor industrycan deposit a film of any material including, for example, a refractorymaterial such as platinum and tungsten, or an insulating material suchas SiO₂. In addition, it is easy to change the energy of sputteringparticles, and it is also possible to control, for example, thecrystalline characteristics, magnetic characteristics, insulationcharacteristics, and stress of a film.

A sputtering cathode used in the sputtering process adopts the followingprinciples. A cathode magnet is arranged in the atmosphere behind atarget arranged in a vacuum, with a partition (for example, a backplate) between them. Magnetic lines of force formed by the cathodemagnet generate a magnetic tunnel that forms an endless annulartrajectory on the flat surface of the target (note that a set of pointsat which a component, perpendicular to the flat surface of the target,of the magnetic tunnel is zero will be referred to as a “magnetictrack”). In this state, supplying a power to the target generates anelectric field in the direction of the normal to the surface of thetarget. Electrons are confined in a region created when the magneticfield and the electric field intersect at right angles. When theconfined electrons collide against gas atoms many times, the gas atomsturn into ions. The electric field on the front surface of the targetaccelerates the ions, thereby causing sputtering.

Since the ions sputter the atoms on the target surface, the targetsurface erodes (to be referred to as “erosion”) over the use time. Whenthe depth of erosion gets close to the thickness of the target, thetarget needs to be exchanged with a new one. If erosion concentrates ona certain position and the erosion speed becomes high, the targetexchange frequency also becomes high, thereby decreasing theavailability of a sputtering apparatus. On the other hand, if the useefficiency of the target is high and the erosion speed is low, thetarget exchange frequency is low, thereby increasing the availability ofa sputtering apparatus.

The erosion speed changes depending on factors such as an electric fieldstrength and a magnetic flux density generated on the front surface ofthe target, a sputtering gas pressure, and a magnetic track shape. Theerosion often selectively proceeds in a partial region (partialdiameter) of the target surface, thereby raising the erosion speed.

To reduce a concentration of erosion, a magnetic track shape, that is, acathode magnet shape (magnetic circuit) has been mainly improved, forwhich many techniques have been proposed. It is, however, difficult fora linear plasma generated on a magnetic track to erode the whole wideflat surface of the target evenly. Therefore, a method of eroding thewhole flat surface of the target by rotating or swinging (performingreciprocation for) the magnetic track (cathode magnet) is used.

Japanese Patent Laid-Open No. 63-317671 proposes a cathode magnet inwhich, as shown in FIG. 25, a second magnetic apparatus 133 is arrangedbetween the N and S poles of a first magnetic apparatus 131 provided onthe rear surface of a target, and the N and S poles of the secondmagnetic apparatus 133 are alternately arranged, in the extendingdirection of the N and S poles of the first magnetic apparatus 131, tobe spaced apart from each other and to face the surface side of thetarget. Note that reference numeral 151 in FIG. 25 denotes the centrodeof an electron e.

In Japanese Patent Laid-Open No. 2001-348663, as shown in FIG. 26, thereare provided a backing plate which is connected with a power supply andhas a function as a cathode electrode, a target attached on the surfaceof the backing plate, and a magnetic circuit arranged on the rearsurface of the backing plate to face the target. The magnetic circuit isarranged so that an erosion region A appearing on the surface of atarget 281 is made into meandering closed curves.

In Japanese Patent No. 4175242, as shown in FIG. 27, there is proposed amagnetron sputtering apparatus in which a target 392 is arranged in avacuum chamber 391. The apparatus includes, on the rear surface of thetarget, an inner magnet 394, an outer magnet 395 which has amagnetization direction opposite to that of the inner magnet 394 andsurrounds the inner magnet 394, and a yoke 396 arranged to face thetarget 392 and to sandwich the inner and outer magnets therebetween, andfurther includes a magnetic circuit for generating arcuate magneticlines of force 397 on the surface of the target 392. Moreover, ahorizontal magnet 311 which has a magnetization component that repelsthose of the outer magnet 395 and inner magnet 394 is inserted betweenthe outer magnet 395 and inner magnet 394 to be parallel to the surfaceof the target 392.

In the methods proposed in Japanese Patent Laid-Open Nos. 63-317671 and2001-348663, the magnetic circuit of the cathode magnet arranged behindthe target is formed into a wavy shape, thereby improving the useefficiency of the target while preventing sputtering particles fromadhering again on the target and also preventing a concentration oferosion.

If, however, the second magnetic apparatus 133 is arranged within thefirst magnetic apparatus 131 as in Japanese Patent Laid-Open No.63-317671 (FIG. 25), the S- and N poles are close to each other. Thatis, magnetic lines of force close directly above the cathode magnet, andthey do not appear on the surface of the target. As a result, a magneticfield does not appear on the target. If the S- and N poles of the secondmagnetic apparatus 133 are moved away from the S- and N poles of thefirst magnetic apparatus 131, magnetic lines of force never closedirectly above the cathode magnet, and a magnetic field appears on thetarget. The method, however, increases the size of the first magneticapparatus 131, and then the cathode becomes large.

On the other hand, in the structure in which an outer magnet 221surrounds a meandering inner magnet 220 with some distance as inJapanese Patent Laid-Open No. 2001-348663 (FIG. 26), the width of theouter magnet 221 which is interlocked with the curved portion of theinner magnet 220 is limited. That is, as the width of the curved portionof the inner magnet 220 becomes large, the width of the outer magnet 221becomes small. Consequently, the magnetic field of the curved portionweakens, and the meander width of the magnetic track becomes small.Furthermore, if a region A is filled with magnets to reserve the meanderwidth, it is possible to widen the meander width but the magnetic fieldstrength becomes locally high, and erosion locally proceeds quickly,which makes the meandering form meaningless.

In Japanese Patent No. 4175242 (FIG. 27), since the horizontal magnet311 is arranged between the outer magnet 395 and the inner magnet 394 tobe parallel to the surface of the target 392, the magnetic fluxdensities of the outer magnet 395 and inner magnet 394 are equal to eachother. Therefore, it is impossible to form a wavy magnetic circuit.

SUMMARY OF THE INVENTION

To solve the above problems, the present invention provides a magnetunit and a magnetron sputtering apparatus which can generate a wavymagnetic track on a target with a sufficient magnetic field strength.

According to one aspect of the present invention, there is provided amagnet unit which includes, on a rear surface of a cathode electrodesupporting a target, a yoke plate made of an antiferromagnetic platematerial, outer peripheral magnets arranged on a plate surface of theyoke plate, and inner magnets that are arranged inside the outerperipheral magnets on the plate surface of the yoke plate and havepolarities different from polarities of the outer peripheral magnets,and forms a magnetic track as a set of regions where tangents ofmagnetic lines of force generated on the target by the outer peripheralmagnets and the inner magnets are parallel to a surface of the target,the unit comprising:

a first magnet element including (a) a first magnet which is provided tostand upright on the plate surface of the yoke plate along a verticaldirection and has a first magnetic pole on a surface facing the platesurface of the yoke plate and a second magnetic pole unlike the firstmagnetic pole on a surface facing away from the plate surface of theyoke plate, (b) a second magnet which is provided to stand upright onthe plate surface of the yoke plate along the vertical direction and hasa third magnetic pole unlike the first magnetic pole on a surface facingthe plate surface of the yoke plate and a fourth magnetic pole unlikethe second pole on the surface facing away from the plate surface of theyoke plate, and (c) a third magnet which is arranged to stand uprightbetween the first magnet and the second magnet, has a fifth magneticpole in a portion facing the second magnetic pole of the first magnetand a sixth magnetic pole unlike the fifth pole on a portion facing thethird magnetic pole of the second magnet, and is magnetized so that aline which connects the fifth magnetic pole and the sixth magnetic poleis diagonally oriented with respect to the flat plate surface of theyoke plate; and

a second magnet element including (d) a fourth magnet which is providedto stand upright on the plate surface of the yoke plate along thevertical direction and has a seventh magnetic pole on the surface facingthe plate surface of the yoke plate and an eighth magnetic pole unlikethe seventh magnetic pole on the surface facing away from the platesurface of the yoke plate, (e) a fifth magnet which is provided to standupright on the plate surface of the yoke plate along the verticaldirection and has a ninth magnetic pole unlike the seventh magnetic poleon the surface facing the plate surface of the yoke plate and a 10thmagnetic pole unlike the eighth pole on the surface facing away from theplate surface of the yoke plate, and (f) a sixth magnet which isarranged to stand upright between the fourth magnet and the fifthmagnet, has an 11th magnetic pole in a portion facing the seventhmagnetic pole of the fourth magnet and a 12th magnetic pole unlike the11th pole in a portion facing the 10th magnetic pole of the fifthmagnet, and is magnetized so that a line which connects the 11thmagnetic pole and the 12th magnetic pole is tilted with respect to theflat plate surface of the yoke plate,

wherein the first magnet element and the second magnet element arealternately arranged in an endless shape.

According to another aspect of the present invention, there is provideda magnet unit which includes, on a rear surface of a rectangular cathodeelectrode supporting a rectangular target, a rectangular yoke plate madeof an antiferromagnetic plate material, outer peripheral magnetsarranged on the yoke plate, and inner magnets that are arranged insidethe outer peripheral magnets on the yoke plate and have polaritiesdifferent from polarities of the outer peripheral magnets, and forms amagnetic track as a set of regions where tangents of magnetic lines offorce generated on the target by the outer peripheral magnets and theinner magnets are parallel to a surface of the target, the unitcomprising:

a first magnet group including a plurality of first magnet-group magnetsarranged along the periphery of the rectangular yoke plate;

a second magnet group including a plurality of second magnet-groupmagnets arranged in a center portion of the rectangular yoke plate; and

a third magnet group including a plurality of third magnet-group magnetsarranged between the first magnet group and the second magnet group tosurround the second magnet group,

wherein the first magnet-group magnets are provided to stand upright ona plate surface of the yoke plate along a vertical direction, and havethe 13th magnetic pole on a surface facing the plate surface of the yokeplate and the 14th magnetic pole unlike the 13th magnetic pole on asurface facing away from the plate surface of the yoke plate,

the second magnet-group magnets are provided to stand upright on theplate surface of the yoke plate along the vertical direction, and havethe 15th magnetic pole unlike the 13th magnetic pole on the surfacefacing the plate surface of the yoke plate and the 16th magnetic poleunlike the 14th magnetic pole on the surface facing away from the platesurface of the yoke plate, and

the third magnet-group magnets include

a seventh magnet which is arranged to stand upright between the firstmagnet-group magnet and the second magnet-group magnet, has a 17thmagnetic pole in a portion facing the 14th magnetic pole of the firstmagnet-group magnet and an 18th magnetic pole unlike the 17th magneticpole in a portion facing the 15th magnetic pole of the secondmagnet-group magnet, and is magnetized so that a line which connects the17th magnetic pole and the 18th magnetic pole is tilted with respect tothe flat plate surface of the yoke, and

an eighth magnet which is arranged to stand upright between the firstmagnet-group magnet and the second magnet-group magnet, has a 19thmagnetic pole in a portion facing the 13th magnetic pole of the firstmagnet-group magnet and a 20th magnetic pole unlike the 19th magneticpole in a portion facing the 16th magnetic pole of the secondmagnet-group magnet, and is magnetized so that a line which connects the19th magnetic pole and the 20th magnetic pole is tilted with respect tothe flat plate surface of the yoke.

According to still another aspect of the present invention, there isprovided a magnetron sputtering apparatus comprising:

a stage capable of supporting a substrate to be processed;

a cathode electrode which is arranged to face the stage, supports atarget, and is supplied with a discharge power; and

a transport mechanism for transporting the stage to the front of thetarget,

wherein a magnet unit as described above is arranged on a rear surfaceof the cathode electrode.

According to the present invention, by alternately arranging a firstmagnet element and a second magnet element in an endless shape, it ispossible to supply an endless meandering magnetic track on the surfaceof a target.

According to the present invention, using a first magnet group providedalong the periphery of a rectangular yoke plate, a second magnet groupprovided in a center portion of the rectangular yoke plate, and thethird magnet group provided between the first magnet group and thesecond magnet group to surround the second magnet group, it is possibleto supply a meandering magnetic track on the surface of a rectangulartarget.

According to the present invention, it is possible to process asubstrate while forming an endless meandering magnetic track on thesurface of a target.

Further features of the present invention will become apparent from thefollowing description of exemplary embodiments (with reference to theattached drawings).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view showing the schematic arrangement of amagnetron sputtering apparatus according to the present invention;

FIG. 2 is a schematic view showing an example of a sputtering apparatushaving a mechanism for performing deposition by a circular cathode,which is applicable to the present invention;

FIG. 3 is a schematic view showing an example of a sputtering apparatushaving a mechanism for causing a substrate to pass through, which isapplicable to the present invention;

FIGS. 4A and 4B are schematic views showing a first magnet elementaccording to the present invention;

FIGS. 5A and 5B are schematic views showing a second magnet elementaccording to the present invention;

FIGS. 6A and 6B are schematic views showing a case in which unlikemagnetic poles are close to each other in the first magnet elementaccording to the present invention;

FIGS. 7A and 7B are schematic views showing a third magnet elementaccording to the present invention;

FIGS. 8A and 8B are schematic views showing a fourth magnet elementaccording to the present invention;

FIG. 9 is a plan view showing a fifth magnet element according to thepresent invention;

FIG. 10 is a perspective view showing the fifth magnet element accordingto the present invention;

FIGS. 11A to 11C are schematic views showing a first magnet unitaccording to the present invention;

FIG. 12 is a schematic view showing a second magnet unit according tothe present invention;

FIG. 13 is a schematic view showing a third magnet unit according to thepresent invention;

FIG. 14 is a schematic view showing a fourth magnet unit according tothe present invention;

FIG. 15 is a schematic view showing a sputtering apparatus to which thepresent invention is applicable;

FIG. 16 is a schematic view showing a fifth magnet unit according to thepresent invention;

FIG. 17A is a schematic view showing a result of extracting a magnetictrack by the fifth magnet unit according to the present invention;

FIG. 17B is a schematic view showing a result of examining an erosiondistribution on a target by the fifth magnet unit according to thepresent invention;

FIG. 18A is a schematic view showing a result of extracting a magnetictrack by a Comparative Example 1 magnet unit;

FIG. 18B is a schematic view showing a result of examining an erosiondistribution on a target by the Comparative Example 1 magnet unit;

FIG. 19A is a schematic view showing a sixth magnet unit according tothe present invention;

FIG. 19B is a schematic view showing a sixth magnet element according tothe present invention;

FIG. 19C is a schematic view showing a seventh magnet element accordingto the present invention;

FIGS. 20A and 20B are plan views showing an eighth magnet elementaccording to the present invention;

FIG. 21 is a perspective view showing the eighth magnet elementaccording to the present invention;

FIG. 22A is a schematic view showing a result of extracting a magnetictrack by the sixth magnet unit according to the present invention;

FIGS. 22B and 22C are schematic views showing a result of examining anerosion distribution on a target by the sixth magnet unit according tothe present invention;

FIGS. 23A and 23B are schematic views showing a Comparative Example 2magnet unit;

FIG. 24A is a schematic view showing a result of extracting a magnetictrack by the Comparative Example 2 magnet unit;

FIGS. 24B and 24C are schematic views showing a result of examining anerosion distribution on a target by the Comparative Example 2 magnetunit;

FIG. 25 is a plan view showing an arrangement example of a magnet unitaccording to the prior art (Japanese Patent Laid-Open No. 63-317671);

FIG. 26 is a horizontal sectional view showing an arrangement example ofa magnet unit according to the prior art (Japanese Patent Laid-Open No.2001-348663); and

FIG. 27 is a sectional view showing the arrangement of a magnetronsputtering apparatus according to the prior art (Japanese Patent No.4175242).

DESCRIPTION OF THE EMBODIMENTS

Embodiments of the present invention will be described below withreference to the accompanying drawings. The present invention, however,is not limited to them.

A magnetron sputtering apparatus according to the present invention willbe explained with reference to FIG. 1. A magnetron sputtering apparatus1 (to be referred to as a “sputtering apparatus” hereinafter) accordingto an embodiment serves as an apparatus which is mounted with a magnetunit 62 (to be described later). FIG. 1 is a schematic view showing theschematic arrangement of the sputtering apparatus according to thepresent invention. FIG. 2 is a schematic view showing an example of asputtering apparatus having a mechanism for performing deposition by acircular cathode while rotating a substrate. FIG. 3 is a schematic viewshowing an example of a sputtering apparatus having a mechanism forcausing a substrate to pass through.

As shown in FIG. 1, the sputtering apparatus 1 of the embodimentincludes a vacuum chamber 2 for partitioning a processing chamber whichcan be evacuated. An exhaust port 3 of the vacuum chamber 2 is connectedwith an exhaust system such as a vacuum pump via a conductance valve(not shown) or the like. The vacuum chamber 2 is connected with a gasintroducing system 4 having a flow controller as a process gasintroducing means, which supplies a process gas at a predetermined flowrate. As the process gas, a rare gas such as argon (Ar), or a single ormixed gas containing nitrogen (N₂) or the like can be used. The vacuumchamber 2 includes a stage 5 for supporting a substrate, and a cathodeelectrode (not shown) which is arranged to face the substrate andsupports a target 6 on its front surface.

The target 6 supported on the front surface of a cathode electrode 61shown in FIG. 2 can be made of a single component such as tantalum (Ta),copper (Cu), or titanium (Ti), or a composition containing two or morecomponents, such as GeSbTe, NiFe, CoPt, or FeCo. The target 6 may bemade of a non-magnetic material such as Ta or Cu, or a magnetic materialsuch as NiFe, CoPt, or FeCo. The target 6 of this embodiment is formedby, for example, a disk-like plate material or rectangular platematerial, and is joined to the front surface (lower surface) of the mainbody of the cathode electrode.

The cathode electrode 61 is connected with a DC power supply capable ofperforming power control, or a high-frequency power supply capable ofperforming power control via a matching unit (neither of which areshown). The magnet unit 62 is arranged on the rear surface of thecathode electrode 61, and can form high-density plasma. That is, thesputtering apparatus 1 of this embodiment introduces a process gas intothe processing chamber within the vacuum chamber 2, causes the powersupply to generate an electric field on the surface of the target 6, andcauses the magnet unit 62 to form a magnetic field on the surface of thetarget 6. With this processing, the sputtering apparatus 1 generates aplasma on the front surface of the target 6 to deposit, on a substrate7, a thin film made of the material of the target 6. The plasma may ofcourse be generated by pulse discharge or the like. Note that thedetailed arrangement of the magnet unit 62 will be described later.

FIG. 2 shows a case in which a plurality of cathode electrodes 61 arearranged to face the stage 5. In this example, a plurality of cathodeelectrodes 61 is arranged. The cathode electrodes 61 are tilted withrespect to the surface of the stage 5 (or substrate 7). The number ofcathode electrodes 61 may be one, as a matter of course. The cathodeelectrodes 61 may be arranged to be parallel to the surface of the stage5 (or substrate 7). Furthermore, the central axis of the stage 5 may ormay not coincide with that of the cathode electrode.

The sputtering apparatus 1 can simultaneously perform sputtering andsubstrate rotation. The stage 5 may incorporate a heating mechanism (notshown) such as a heater or a cooling mechanism (not shown) such as arefrigerator.

An example of the substrate 7 includes a semiconductor wafer. Thesubstrate is solely fixed on the stage 5 or a tray mounted with thesubstrate is fixed on the stage 5.

As shown in FIG. 3, there may be arranged a substrate transportmechanism 9 including a stage rotating mechanism for rotating, along acircle having the mounting surface of the stage 5 as its tangent, thecircular stage 5 supporting the substrate 7. In this arrangementexample, the stage 5 has a rotation axis 9 a extending in thelongitudinal direction of the rectangular target 6. The substrate 7passes through in front of the target 6 by rotating the stage 5 aboutthe rotation axis 9 a. The magnet unit 62 is arranged on the rearsurface of the cathode electrode, and can form a high-density plasma.Note that the detailed arrangement of the magnet unit 62 will bedescribed later.

The first feature of a magnet unit according to this embodiment is thata first magnet element 40 includes a first magnet which is provided tostand upright on the plate surface of a yoke plate (magnetic plate)along the vertical direction and has a first magnetic pole (N or S pole)on a surface facing the plate surface of the yoke plate (magnetic plate)and a second magnetic pole (N or S pole) unlike the first magnetic poleon a surface (the target side) facing away from the plate surface of theyoke plate (magnetic plate), a second magnet which is provided to standupright on the plate surface of the yoke plate (magnetic plate) alongthe vertical direction and has a third magnetic pole (N or S pole)unlike the first magnetic pole (N or S pole) on the surface facing theplate surface of the yoke plate (magnetic plate) and a fourth magneticpole (N or S pole) unlike the second pole (N or S pole) on the surface(the target side) facing away from the plate surface of the yoke plate(magnetic plate), and a third magnet which is arranged to stand uprightbetween the first magnet and the second magnet, has a fifth magneticpole (N or S pole) in a portion facing the second magnetic pole (N or Spole) of the first magnet and a sixth magnetic pole (N or S pole) unlikethe fifth pole (N or S pole) on a portion facing the third magnetic pole(N or S pole) of the second magnet, and is magnetized so that a linewhich connects the fifth magnetic pole (N or S pole) and the sixthmagnetic pole (N or S pole) is tilted with respect to the flat platesurface of the yoke plate (magnetic plate). The first magnet element 40will be described in detail later.

The second feature of the magnet unit according to this embodiment isthat a second magnet element 41 includes a fourth magnet which isprovided to stand upright on the plate surface of a yoke plate (magneticplate) along the vertical direction and has a seventh magnetic pole (Nor S pole) on a surface facing the plate surface of the yoke plate(magnetic plate) and an eighth magnetic pole (N or S pole) unlike theseventh magnetic pole (N or S pole) on a surface (the target side)facing away from the plate surface of the yoke plate (magnetic plate), afifth magnet which is provided to stand upright on the plate surface ofthe yoke plate (magnetic plate) along the vertical direction and has aninth magnetic pole (N or S pole) unlike the seventh magnetic pole (N orS pole) on the surface facing the plate surface of the yoke plate(magnetic plate) and a 10th magnetic pole (N or S pole) unlike theeighth pole (N or S pole) on the surface (the target side) facing awayfrom the plate surface of the yoke plate (magnetic plate), and a sixthmagnet which is arranged to stand upright between the fourth magnet andthe fifth magnet, has an 11th magnetic pole (N or S pole) in a portionfacing the seventh magnetic pole (N or S pole) of the fourth magnet anda 12th magnetic pole (N or S pole) unlike the 11th magnetic pole (N or Spole) in a portion facing the 10th magnetic pole (N or S pole) of thefifth magnet, and is magnetized so that a line which connects the 10thmagnetic pole (N or S pole) and the 11th magnetic pole (N or S pole) istilted with respect to the flat plate surface of the yoke plate(magnetic plate). The second magnet element 41 will be described indetail later.

The third feature of the magnet unit according to this embodiment isthat the first magnet element and the second magnet element arealternately arranged in an endless shape. A first magnet unit 70 (FIGS.11A to 11C), a second magnet unit 80 (FIG. 12), a third magnet unit 90(FIG. 13), and a fourth magnet unit 100 (FIG. 14) each of which isformed by alternately arranging the first magnet element and the secondmagnet element will be described in detail later.

A first magnet element 40 will be explained with reference to FIGS. 4Aand 4B to which the present invention is applicable. FIG. 4A is asectional view showing the first magnet element 40. FIG. 4B is a planview showing the first magnet element 40. As shown in FIG. 4A, the firstmagnet element 40 has an arrangement in which a first magnet 411-1 and asecond magnet 412-1 are fixed on the two end portions of a magneticplate (yoke plate) 410 by an adhesive, and a third magnet 413-1 is fixedbetween the first magnet 411-1 and the second magnet 412-1 by theadhesive. In this example, an epoxy adhesive is used.

The magnetic poles of the first magnet element 40 will be described. Asshown in FIG. 4A, the first magnet 411-1 and the second magnet 412-1have magnetic poles parallel to the direction of the normal to thesurface of the magnetic plate 410, and the magnetic poles of the firstmagnet 411-1 are oriented in a direction opposite to that of themagnetic poles of the second magnet 412-1. More specifically, in thisembodiment, the first magnet 411-1 is arranged to stand upright on theplate surface of the yoke plate (magnetic plate) 410 along the verticaldirection. The first magnet 411-1 has the first magnetic pole (S pole)on a surface facing the plate surface of the yoke plate (magnetic plate)410, and the second magnetic pole (N pole) unlike the first magneticpole (S pole) on a surface (the target side) facing away from the platesurface of the yoke plate (magnetic plate) 410. The second magnet 412-1is provided to stand upright on the plate surface of the yoke plate(magnetic plate) 410 along the vertical direction. The second magnet412-1 has the third magnetic pole (N pole) unlike the first magneticpole (S pole) on the surface facing the plate surface of the yoke plate(magnetic plate) 410, and the fourth magnetic pole (S pole) unlike thesecond magnetic pole (N pole) on the surface (the target side) facingaway from the plate surface of the yoke plate (magnetic plate) 410.

Consequently, on the surface facing the target 6, the second magneticpole (N pole) appears in the first magnet 411-1 and the fourth magneticpole (S pole) appears in the second magnet 412-1. The third magnet 413-1is arranged to stand upright between the first magnet 411-1 and thesecond magnet 412-1. The third magnet 413-1 has the fifth magnetic pole(N pole) in a portion facing the second magnetic pole (N pole) of thefirst magnet 411-1, and the sixth magnetic pole (S pole) unlike thefifth magnetic pole (N pole) in a portion facing the third magnetic pole(N pole) of the second magnet 412-1. The third magnet 413-1 ismagnetized so that a line which connects the fifth magnetic pole (Npole) and the sixth magnetic pole (S pole) is tilted with respect to theflat plate surface of the yoke plate (magnetic plate) 410. That is, theline which connects the fifth magnetic pole (N pole) and the sixthmagnetic pole (S pole) of the third magnet 413-1 forms an angle θ in adirection from the third magnetic pole (N pole) of the second magnet412-1 to the second magnetic pole (N pole) of the first magnet 411-1,that is, a direction from a direction parallel to the surface of themagnetic plate 410 to the target 6. The third magnet 413-1 has magneticpoles forming an angle γ in the clockwise direction with respect to aline which connects the fourth magnetic pole (S pole) of the secondmagnet 412-1 and the second magnetic pole (N pole) of the first magnet411-1, that is, an imaginary line 416, a perpendicular dropped to a side414 or 415 shown in FIG. 4B.

In other words, the line which connects the fifth magnetic pole (N pole)and sixth magnetic pole (S pole) of the third magnet 413-1 forms anangle of 60° or smaller in the clockwise direction with respect to theline which connects the second magnetic pole (N pole) of the firstmagnet 411-1 and the fourth magnetic pole (S pole) of the second magnet412-1 along the flat plate surface of the yoke plate (magnetic plate)410. The polarity of the fifth magnetic pole (N pole) of the thirdmagnet 413-1, therefore, repels that of the second magnetic pole (Npole) of the first magnet 411-1.

The magnetic poles of the second magnet element 41 will be describedwith reference to FIGS. 5A and 5B. FIG. 5A is a sectional view showingthe second magnet element 41. FIG. 5B is a plan view showing the secondmagnet element 41. As shown in FIG. 5A, the second magnet element 41 hasan arrangement in which a fourth magnet 411-2 and a fifth magnet 412-2are fixed on the two end portions of the magnetic plate (yoke plate) 410by an adhesive, and a sixth magnet 413-2 is fixed between the fourthmagnet 411-2 and the fifth magnet 412-2 by the adhesive. In thisexample, an epoxy adhesive is used.

The magnetic poles of the second magnet element 41 will be explainednext. As shown in FIG. 5A, the fourth magnet 411-2 and the fifth magnet412-2 have magnetic poles parallel to the direction of the normal to thesurface of the magnetic plate 410, and the magnetic poles of the fourthmagnet 411-2 are oriented in a direction opposite to that of themagnetic poles of the fifth magnet 412-2. More specifically, in thisembodiment, the fourth magnet 411-2 is provided to stand upright on theplate surface of the yoke plate (magnetic plate) 410 along the verticaldirection. The fourth magnet 411-2 has the seventh magnetic pole (Spole) on a surface facing the plate surface of the yoke plate (magneticplate) 410, and the eighth magnetic pole (N pole) unlike the seventhmagnetic pole (S pole) on a surface (the target side) facing away fromthe plate surface of the yoke plate (magnetic plate) 410. The fifthmagnet 412-2 is provided to stand upright on the plate surface of theyoke plate (magnetic plate) 410 along the vertical direction. The fifthmagnet 412-2 has the ninth magnetic pole (N pole) unlike the seventhmagnetic pole (S pole) on the surface facing the plate surface of theyoke plate (magnetic plate) 410, and the 10th magnetic pole (S pole)unlike the eighth magnetic pole (N pole) on the surface (the targetside) facing away from the plate surface of the yoke plate (magneticplate) 410. Consequently, on the surface facing the target, the eighthmagnetic pole (N pole) appears in the fourth magnet 411-2 and the 10thmagnetic pole (S pole) appears in the fifth magnet 412-2.

The sixth magnet 413-2 is arranged to stand upright between the fourthmagnet 411-2 and the fifth magnet 412-2. The sixth magnet 413-2 has the11th magnetic pole (N pole) in a portion facing the seventh magneticpole (S pole) of the fourth magnet 411-2, and the 12th magnetic pole (Spole) unlike the 11th magnetic pole (N pole) in a portion facing the10th magnetic pole (N pole) of the fifth magnet 412-2. The sixth magnet413-2 is magnetized so that a line which connects the 10th magnetic pole(S pole) and the 11th magnetic pole (N pole) is tilted with respect tothe flat plate surface of the yoke plate (magnetic plate) 410.Consequently, the line which connects the 10th magnetic pole (S pole)and the 11th magnetic pole (N pole) of the sixth magnet 413-2 forms theangle θ in a direction from the 10th magnetic pole (S pole) of the fifthmagnet 412-2 to the seventh magnetic pole (S pole) of the fourth magnet411-2, that is, a direction from a direction parallel to the surface ofthe magnetic plate 410 to the rear surface of the yoke plate 410. Thesixth magnet 413-2 has magnetic poles forming the angle γ in thecounterclockwise direction with respect to a line which connects the10th magnetic pole (S pole) of the fifth magnet 412-2 and the eighthmagnetic pole (N pole) of the fourth magnet 411-2, that is, theimaginary line 416, a perpendicular dropped to the side 414 or 415 shownin FIG. 5B. In other words, the line which connects the 11th magneticpole (S pole) and 12th magnetic pole (N pole) of the sixth magnet 413-2forms an angle of 60° or smaller in the counterclockwise direction withrespect to the line which connects the eighth magnetic pole (N pole) ofthe fourth magnet 411-2 and the 10th magnetic pole (S pole) of the fifthmagnet 412-2 along the flat plate surface of the yoke plate (magneticplate) 410. The polarity of the 12th magnetic pole (S pole) of the sixthmagnet 413-2, therefore, repels that of the 10th magnetic pole (S pole)of the fifth magnet 412-2.

The shape of the magnetic lines of force formed by the first magnetelement 40 will be explained with reference to FIGS. 4A and 4B. Asdescribed above, on the surface facing the target 6, the S pole appearsin the second magnet 412-1 of the first magnet element 40, and the Npole appears in the first magnet 411-1 of the first magnet element 40.Of the magnetic poles of the third magnet 413-1, the first componentparallel to the normal to the surface of the magnetic plate 410 isoriented from the N pole of the second magnet 412-1 to the N pole of thefirst magnet 411-1. On the other hand, of the poles of the third magnet413-1, the second component perpendicular to the normal to the surfaceof the magnetic plate 410 is oriented from the S pole of the secondmagnet 412-1 to the N pole of the first magnet 411-1. In the firstmagnet element 40 in this example, the number of magnetic lines of force(a magnetic flux density) exiting the N pole of the first magnet whichfaces the surface of the target 6 increases. A region in which, of themagnetic lines of force which are oriented from the N pole of the firstmagnet 411-1 to the S pole of the second magnet 412-1, componentsparallel to the direction of the normal to the surface of the target 6are zero shifts to the second magnet 412-1 side.

The shape of the magnetic lines of force formed by the second magnetelement 41 will be explained with reference to FIGS. 5A and 5B.Similarly to the first magnet 411-1 and the second magnet 412-1 of thefirst magnet element, on the surface facing the target, the S poleappears in the fifth magnet 412-2 of the second magnet element 41, andthe N pole appears in the fourth magnet 411-2 of the second magnetelement 41. Of the magnetic poles of the sixth magnet 413-2, the firstcomponent parallel to the normal to the surface of the magnetic plate410 is oriented from the S pole of the fifth magnet 412-2 to the S poleof the fourth magnet 411-2. On the other hand, of the poles of the sixthmagnet 413-2, the second component perpendicular to the normal tosurface of the magnetic plate 410 is oriented from the S pole of thefifth magnet 412-2 to the N pole of the fourth magnet 411-2. In thesecond magnet element 41 in this example, the number of magnetic linesof force entering the S pole of the fifth magnet 412-2 which faces thesurface of the target 6 increases. A region in which, of the magneticlines of force which are oriented from the N pole of the fourth magnet411-2 to the S pole of the fifth magnet 412-2, components parallel tothe direction of the normal to the surface of the target 6 are zeroshifts to the fourth magnet 411-2 side.

Note that the directions and values of θ and γ shown in FIGS. 4A, 4B,5A, and 5B are merely examples, and “−70°≦θ<10° or 10°<θ≦70°” and“−60°≦γ≦60°” are desirable. This will be described with reference toFIGS. 6A and 6B. If the absolute value of θ exceeds 70°, the polarity ofthe fifth magnetic pole (N pole) of the third magnet 413-1 has adirection almost perpendicular to the surface of the magnetic plate 410(FIG. 6A). Therefore, unlike magnetic poles (in FIG. 6A, the S pole ofthe second magnet 412-1 and the N pole of the third magnet 431-1) comeclose to each other, and the magnetic lines of force close directlyabove the magnets 412-1 and 413-1, thereby decreasing the number ofmagnetic lines of force on the target. Similarly, if the absolute valueof γ exceeds 60°, the sixth magnetic pole (S pole) of the third magnet413-1 comes close to the second magnetic pole (N pole) of the firstmagnet 411-1 and the fifth magnetic pole (N pole) of the third magnet413-1 comes close to the fourth magnetic pole (S pole) of the secondmagnet 412-1 (FIG. 6B). Therefore, the magnetic lines of force closedirectly above the magnets 411-1, 412-2, and 413-1, thereby decreasingthe number of magnetic lines of force on the target. If the value(absolute value) of θ is equal to or smaller than 10°, a region in whichcomponents, parallel to the direction of the normal to the surface ofthe target, of the magnetic lines of force on the surface of the magnetelement are zero has a small shift amount. FIGS. 6A and 6B show thefirst magnet element 40 in this case. The same goes for the secondmagnet element 41 with respect to the directions and values of θ and γ.

The definition of a minus sign (−) for an angle will be described. −θindicates an angle formed when a component, parallel to the normal tothe surface of the magnetic plate 410, of the magnetic poles of thethird magnet 413-1 or the sixth magnet 413-2 is oriented in the samedirection as that of the magnetic poles of the second magnet 412-1 orthe fifth magnet 412-2. −γ indicates an angle, with respect to theimaginary line 416, formed by the direction of the N pole of the thirdmagnet 413-1 which has rotated in the clockwise direction. That is, inthe first magnet element 40 shown in FIGS. 4A and 4B, since the N and Spoles of the third magnet 413-1 are oriented in a direction opposite tothat of the N and S poles of the second magnet 412-1, θ is positive.Since the direction of the N pole of the third magnet 413-1 has rotatedin the clockwise direction with respect to the imaginary line 416, γ isnegative. On the other hand, in the second magnet element 41 shown inFIGS. 5A and 5B, θ is negative and γ is positive.

According to the above-described method, it is apparent that the presentinvention is readily applicable to a trapezoidal third magnet element 50shown in FIGS. 7A and 7B or a trapezoidal fourth magnet element 51 shownin FIGS. 8A and 8B. Note that, in the third magnet element 50 shown inFIGS. 7A and 7B, the volume of an eighth magnet 512-1 corresponding tothe second magnet 412-1 of the first magnet element 40 shown in FIGS. 4Aand 4B is smaller than that of a seventh magnet 511-1 corresponding tothe first magnet 411-1 of the first magnet element 40 shown in FIGS. 4Aand 4B. Except for this, the third magnet element 50 has the samearrangement as that of the first magnet element 40 shown in FIGS. 4A and4B. Note that a ninth magnet 513-1 shown in FIGS. 7A and 7B correspondsto the third magnet 413-1 of the first magnet element 40 shown in FIGS.4A and 4B. A 10th magnet 511-2, an 11th magnet 512-2, and a 12th magnet513-2 shown in FIGS. 8A and 8B correspond to the fourth magnet 411-2,the fifth magnet 412-2, and the sixth magnet 413-2 of the second magnetelement 41 shown in FIGS. 5A and 5B, respectively. FIG. 7A is asectional view showing the third magnet element 50. FIG. 7B is a planview showing the third magnet element 50. Furthermore, in the fourthmagnet element 51 shown in FIGS. 8A and 8B, the volume of the 11thmagnet 512-2 corresponding to the fifth magnet 412-2 of the secondmagnet element 41 shown in FIGS. 5A and 5B is smaller than that of the10th magnet 511-2 corresponding to the fourth magnet 411-2 of the secondmagnet element 41 shown in FIGS. 5A and 5B. Except for this, the fourthmagnet element 51 has the same arrangement as that of the second magnetelement 41 shown in FIGS. 5A and 5B. FIG. 8A is a sectional view showingthe fourth magnet element 51. FIG. 8B is a plan view showing the fourthmagnet element 51.

A region in which components, parallel to the direction of the normal tothe surface of a target, of magnetic lines of force appearing on thesurface of the target are zero in FIGS. 7A and 7B or FIGS. 8A and 8B isdifferent from that of the first magnet element 40 shown in FIGS. 4A and4B or the second magnet element 41 shown in FIGS. 5A and 5B. The shapeshown in FIGS. 7A and 7B or FIGS. 8A and 8B is preferable to an exampleshown in FIG. 14. In this example, the shape becomes narrower on the Spole side (the magnet 512-1 or 512-2). A gap between neighboring magnetelements is eliminated or decreased by arranging such magnet elements inan arc with its center on the S pole side, thereby enabling to suppressa decrease in number of magnetic lines of force near the N pole side(the magnet 511-1 or 511-2).

A fifth magnet element 60 shown in FIGS. 9 and 10 is also an example towhich the present invention is applicable. FIG. 9 is a plan view showingthe fifth magnet element. In the fifth magnet element 60, 13th to 19thmagnets 611 to 617 are fixed on a magnetic plate 610. The U-shaped 13thmagnet 611 is provided on the rectangular magnetic plate 610. The 13thmagnet 611 has magnetic poles parallel to the direction of the normal tothe surface of the magnetic plate 610, and has the N pole on the sidefacing a target and the S pole on the side facing the magnetic plate610. The 14th magnet 612 is provided within the U-shaped 13th magnet611. The 14th magnet 612 has the magnetic poles parallel to thedirection of the normal to the surface of the magnetic plate 610similarly to the 13th magnet 611, but the magnetic poles have adirection opposite to that of the magnetic poles of the 13th magnet 611.The 15th magnet 613, 16th magnet 614, 17th magnet 615, 18th magnet 616,and 19th magnet 617 are inserted between the 14th magnet 612 and the13th magnet 611 to form a U-shape. The angle γ of the magnetic poles isas follows.

The angle γ of the magnetic poles of the 17th magnet 615 is 0° withrespect to an imaginary line 625, a perpendicular dropped to aninterface between the 14th magnet 612 and the 17th magnet 615. The 17thmagnet 615 forms the angle θ in a direction from the N pole of the 14thmagnet 612 to the N pole of the 13th magnet 611, that is, a directionfrom a direction parallel to the surface of the magnetic plate 610 tothe target 6. The angle γ of the magnetic poles of the 16th magnet 614is negative with respect to an imaginary line 624, a perpendiculardropped to the imaginary line 625. The definition of the minus sign (−)of the angle is the same as that for the first to fourth magnetelements. Assume that −γ indicates an angle, with respect to theimaginary line 624, formed by the direction of the N pole of each of the15th to 19th magnets 613 to 617 which has rotated in the clockwisedirection. Since the N pole of the 16th magnet 614 has rotated in theclockwise direction with respect to the imaginary line 624, therefore, γis negative. To the contrary, the N pole of the 15th magnet 613 hasrotated in the counterclockwise direction with respect to the imaginaryline 624, γ is positive. The 18th magnet 616 and the 19th magnet 617have magnetic poles symmetrical to those of the 16th magnet 614 and the15th magnet 613 with respect to the imaginary line 625, respectively.

FIG. 10 is a perspective view for easy understanding of the magneticpole direction of each magnet of the fifth magnet element 60. With theshape of the fifth magnet element 60, it is possible to form ameandering erosion track even in the two end portions of a rectangularcathode magnet (to be described later), and to prevent a concentratederosion portion from occurring on the target by swinging the cathodemagnet.

FIGS. 11A to 11C show the first magnet unit 70 to present part of anarrangement obtained by alternately arranging the first magnet element40 described with reference to FIGS. 4A and 4B and the second magnetelement 41 described with reference to FIGS. 5A and 5B so that likemagnetic poles are adjacent to each other. FIG. 11A is a plan viewshowing the first magnet unit 70. FIG. 11B is a plan view showing thefirst magnet element 40. FIG. 11C is a plan view showing the secondmagnet element 41. In this example, the first magnet element 40 and thesecond magnet element 41 are spaced apart from each other. The distance(separation) between them is preferably 30 mm or shorter. With thisarrangement, a group of points at which components, parallel to thenormal to the surface of a target (not shown), of a magnetic fieldappearing on the target are zero, that is, a magnetic track 710 forms awavy shape. If the distance is 30 mm or longer, the magnetic track 710does not form a wavy shape.

FIG. 12 shows the second magnet unit 80 to present part of anarrangement obtained by alternately arranging the first magnet element40 described with reference to FIGS. 4A and 4B and the second magnetelement 41 described with reference to FIGS. 5A and 5B so that likemagnetic poles are in tight contact with each other. With thisarrangement, a group of points at which components, parallel to thenormal to the surface of a target (not shown), of a magnetic fieldappearing on the target are zero, that is, a magnetic track 810 forms awavy shape.

A difference between the arrangements in FIGS. 11A and 12 is thedistance between the first magnet element 40 and the second magnetelement 41 which are linearly arranged. By giving a gap (interval) asshown in FIG. 11A, a magnetic field component parallel to the surface ofthe target (not shown) in the magnetic track appearing on the surface ofthe target becomes small. To the contrary, it is possible to increase amagnetic field component on the target by densely arranging the magnetelements, as shown in FIG. 12.

Referring to FIG. 13, the first magnet element 40 and the second magnetelement 41 are alternately arranged along an arcuate imaginary line(circle) 900, and a wavy magnetic track 910 appears almost along theimaginary line (circle) 900. A magnet unit including outer peripheralmagnets and inner magnets which are arranged inside the outer peripheralmagnets and have polarities different from those of the outer peripheralmagnets is formed on the plate surface of a yoke plate.

FIG. 14 is a view showing a case in which a wavy magnetic track 1001occurs along an arcuate imaginary line 1000 by alternately arranging thethird magnet element 50 and the fourth magnet element 51 so that likemagnetic poles are in contact with each other. Note that when the value(absolute value) of θ becomes 10° or smaller, the shift amount of aregion where components, parallel to the direction of the normal to thesurface of a target, of magnetic lines of force on the surface of amagnet element are zero becomes small, and therefore, the magnetic trackdoes not form a wavy shape. The same goes for the examples shown inFIGS. 11A to 11C, 12, and 13.

Example 1

In Example 1, the shape of a magnetic track is examined using a circularcathode electrode 203 arranged in a sputtering apparatus 200 (FIG. 15)to which the present invention is applicable. A magnet unit 201 is asshown in FIG. 16. A magnet used in the fifth magnet unit 201 is made ofNdFeB, which has a maximum energy product of 381 KJ/m³ (48 MGOe). Thediameter of the fifth magnet unit 201 is 370 mm, and the height of amagnet portion is 30 mm. In the fifth magnet unit 201, 24 magnetelements are fixed along an inverted-heart shape. The 24 magnet elementsinclude the first magnet element 40 shown in FIGS. 4A and 4B, the secondmagnet element 41 shown in FIGS. 5A and 5B, the third magnet element 50shown in FIGS. 7A and 7B, and the fourth magnet element 51 shown inFIGS. 8A and 8B, and the first to fourth magnet elements are providedalong the inverted-heart shape shown in FIG. 16 according to thepolarities and positions shown in table 1 below.

Note that SS400 with a thickness of 12 mm was used as a magnetic plateserving as a yoke plate. Table 1 below shows a positional relationshipand the magnetic pole direction of each magnet element of the fifthmagnet unit 201. Note that it is also possible to form the fifth magnetunit 201 by fixing the 24 magnet elements in, for example, a circle orellipse. That is, it is possible to fix the 24 magnet elements in anyshape as long as the shape is endless.

TABLE 1 No. θ° γ° 1 −45 0 2 45 0 3 −45 0 4 45 0 5 −45 0 6 45 0 7 −45 0 845 0 9 −45 0 10 45 0 11 −45 0 12 45 0 13 −45 0 14 45 0 15 −45 0 16 45 017 −45 0 18 45 0 19 −45 0 20 45 0 21 −45 0 22 45 0 23 −45 0 24 45 0

Nos. 1 to 24 in table 1 represent numbers given in the fifth magnet unit201 shown in FIG. 16. The first magnet elements 40 are arranged atpositions indicated by Nos. 2, 4, 6, 8, 10, and 18 in table 1. Thesecond magnet elements 41 are arranged at positions indicated by Nos. 1,3, 5, 7, 9, 11, 17, and 19 in table 1. The third magnet elements 50 arearranged at positions indicated by Nos. 12, 14, 16, 20, 22, and 24 intable 1. The fourth magnet elements 51 are arranged at positionsindicated by Nos. 13, 15, 21, and 23 in table 1.

A target 202 shown in FIG. 17A is fixed on the front of the fifth magnetunit 201 via a rear plate (not shown). In this case, the distancebetween the surface of the target 202 and that of the fifth magnet unit201 is 14 mm. The target 202 is made of an FeCo alloy, which has athickness of 3 mm and a diameter of 376 mm.

To examine a magnetic track on the target 202, the circular cathodeelectrode 203 was arranged in a magnetic field measurement device (notshown). A probe connected with the magnetic field measurement device waspositioned at a height of 1.0 mm directly above the target, and scannedin the plane direction of the target 202 while keeping its height. Inthis case, scanning directions were the x and y directions in FIG. 16and the value of a magnetic flux density was acquired in the x, y, and zdirections. Note that a computer (not shown) controlled the scanoperation and magnetic flux density value acquisition of the probe.

As a result of extracting a region where components (compositecomponents in the x and y directions=(x2+y2)1/2) of the obtainedmagnetic flux density, which were parallel to the surface of the targetand had a value of 50 mT or larger, and points at which components,parallel to the normal to the surface of the target, of the obtainedmagnetic flux density were zero, that is, a magnetic track, it was foundthat a magnetic track 210 had a wavy shape as shown in FIG. 17A. Notethat if components, parallel to the surface of the target, of themagnetic flux density on the magnetic track have a value of 50 mT orlarger (a region 211), a stable electric discharge is possible. It isfound from this result that it is possible to obtain a magnetic fieldstrength with which a stable electric discharge is possible whileobtaining the wavy magnetic track 210.

The fifth magnet unit 201 was attached to the circular cathode electrode203 shown in FIG. 15, and was caused to discharge while being rotatedparallel to the surface of the target 202, thereby performing sputteringdeposition. When examining an erosion distribution on the target 202after using 60 kWh, a result shown in FIG. 17B was obtained. The deepestportion of an erosion portion presents a “gentle valley” shape, therebypreventing a concentration of erosion.

Comparative Example 1

To ensure that the present invention is effective, a case in which aconventional magnet element is used will be described as ComparativeExample 1. Assume that a magnet unit (to be referred to as “ComparativeExample 1 magnet unit” hereinafter) according to Comparative Example 1has the same arrangement as that of a fifth magnet unit 201. A magnetused in the Comparative Example 1 magnet unit is made of NdFeB which hasa maximum energy product of 381 KJ/m³ (48 MGOe). SS400 with a thicknessof 12 mm is used as a magnetic plate serving as a yoke plate. TheComparative Example 1 magnet unit has an outermost diameter of 370 mmand a magnet portion has a height of 30 mm. The Comparative Example 1magnet unit is formed by fixing 24 magnet elements along aninverted-heart shape. Each of the 24 magnet elements has the shape of afirst magnet element 40 shown in FIGS. 4A and 4B, a second magnetelement 41 shown in FIGS. 5A and 5B, a third magnet element 50 shown inFIGS. 7A and 7B, or a fourth magnet element 51 shown in FIGS. 8A and 8B.The above-described conditions are the same as those for the fifthmagnet unit 201. Note that, as shown in table 2 below, a point differentfrom the magnet unit 201 is that θ and γ are all 0°. Table 2 below showsa positional relationship and a magnetic pole direction of each magnetelement of the Comparative Example 1 magnet unit.

TABLE 2 No. θ° γ° 1 0 0 2 0 0 3 0 0 4 0 0 5 0 0 6 0 0 7 0 0 8 0 0 9 0 010 0 0 11 0 0 12 0 0 13 0 0 14 0 0 15 0 0 16 0 0 17 0 0 18 0 0 19 0 0 200 0 21 0 0 22 0 0 23 0 0 24 0 0

Nos. 1 to 24 in table 2 represent numbers given in the fifth magnet unit201 shown in FIG. 16. The first magnet elements 40 are arranged atpositions indicated by Nos. 2, 4, 6, 8, 10, and 18 in table 2. Thesecond magnet elements 41 are arranged at positions indicated by Nos. 1,3, 5, 7, 9, 11, 17, and 19 in table 2. The third magnet elements 50 arearranged at positions indicated by Nos. 12, 14, 16, 20, 22, and 24 intable 2. The fourth magnet elements 51 are arranged at positionsindicated by Nos. 13, 15, 21, and 23 in table 2.

A target 202 shown in FIG. 18A is fixed on the front of the ComparativeExample 1 magnet unit via a rear plate (not shown). In this case, thedistance between the surface of the target 202 and that of theComparative Example 1 magnet unit is 14 mm. The target 202 is made of anFeCo alloy, which has a thickness of 3 mm and a diameter of 376 mm.

To examine a magnetic track on the target 202, a circular cathodeelectrode 203 shown in FIG. 15 was arranged in a magnetic fieldmeasurement device (not shown). A probe connected with the magneticfield measurement device was positioned at a height of 1.0 mm directlyabove the target, and scanned in the plane direction of the target 202while keeping its height. In this case, scanning directions were the xand y directions in FIG. 16, and the value of a magnetic flux densitywas acquired in the x, y, and z directions. Note that a computer (notshown) controlled the scan operation and magnetic flux density valueacquisition of the probe.

A result shown in FIG. 18A was obtained by extracting a region 251 inwhich components (composite components in the x and ydirections=(x2+y2)1/2) of the obtained magnetic flux density, which wereparallel to the surface of the target and had a value of 50 mT orlarger, and points at which components, parallel to the normal to thesurface of the target, of the obtained magnetic flux density were zero,that is, a magnetic track 252. The magnetic track never has a wave shapein Comparative Example 1, as a matter of course.

The Comparative Example 1 magnet unit was attached to the circularcathode electrode 203 shown in FIG. 15, and was caused to dischargewhile being rotated parallel to the surface of the target 202, therebyperforming sputtering deposition. When examining an erosion distributionon the target 202 after using 40 kWh, a result shown in FIG. 18B wasobtained. The deepest portion of an erosion portion presents a “sharpvalley” shape and it is thus found that the use efficiency of the targetdecreased due to the concentration of erosion. The effects of thepresent invention become apparent by comparing FIG. 17B with FIG. 18B.

Example 2

In Example 2, dimensions were the same as those in Example 1, thematerials of a magnet and target were changed, and then the shape of amagnetic track appearing on the surface of a target was examined. Amethod of using a magnetic field measurement device is the same as thatin Example 1. A magnet used in a fifth magnet unit 201 is made of anSmSo-based material which has a maximum energy product of 151 KJ/m³ (19MGOe). The target is made of Ta (a non-magnetic material). Thiscombination causes the magnetic track to have a wavy shape, and it wasfound that components, parallel to the surface of the target, of amagnetic flux density on the magnetic track had a value of 50 mT orlarger.

That is, by applying the present invention, it becomes possible toobtain a magnetic flux density with which a discharge is possible whileobtaining a wavy magnetic track regardless of a magnet material.

Example 3

In Example 3, the shape of a magnetic track was examined using arectangular cathode electrode arranged in a sputtering apparatus 3 shownin FIG. 3. A target 6 is fixed on the front of the sixth magnet unit 600via a rear plate (not shown). In this case, the distance between thesurface of the target 6 and that of the sixth magnet unit 600 is 14 mm.The target 6 is made of an FeCo alloy, which has a size of 130 mm×470mm×3 mm (thickness).

The shape of the sixth magnet unit 600 is as shown in FIGS. 19A to 19C.A magnet used in the sixth magnet unit 600 is made of NdFeB which has amaximum energy product of 381 KJ/m³ (48 MGOe). The unit 600 has aminor-axis length of 90 mm, a major-axis length of 430 mm, and amagnet-portion height of 35 mm.

The sixth magnet unit 600 is formed by a first magnet group 60 aincluding a plurality of first magnet-group magnets arranged along theperiphery of a rectangular magnetic plate (yoke plate) 310, a secondmagnet group 60 b including a plurality of second magnet-group magnetsarranged in the center portion of the rectangular magnetic plate (yokeplate) 310, and a third magnet group 60 c including a plurality of thirdmagnet-group magnets arranged between the first magnet group 60 a andthe second magnet group 60 b to surround the second magnet group 60 b.The first magnet-group magnets are provided to stand upright on theplate surface of the rectangular magnetic plate (yoke plate) 310 alongthe vertical direction, and have a 13th magnetic pole (S pole) on asurface facing the plate surface of the rectangular magnetic plate (yokeplate) 310 and a 14th magnetic pole (N pole) unlike the 13th magneticpole (S pole) on a surface facing away from the plate surface of therectangular magnetic plate (yoke plate) 310.

Referring to FIG. 19A, the first magnet-group magnets include aplurality of magnets each having the N pole in the x-axis direction. Thefirst magnet-group magnets correspond to a 20th magnet 311-1 of a sixthmagnet element 301, a 23rd magnet 311-2 of a seventh magnet element 302,and a magnets 303-1 or 303-2 of an eighth magnet element 303 (all ofwhich will be described later). The second magnet-group magnets areprovided to stand upright on the plate surface of the rectangularmagnetic plate (yoke plate) 310 along the vertical direction, and have a15th magnetic pole (N pole) unlike the 13th magnetic pole (S pole) onthe surface facing the plate surface of the rectangular magnetic plate(yoke plate) 310 and a 16th magnetic pole (S pole) unlike the 14thmagnetic pole (N pole) on the surface facing away from the plate surfaceof the yoke plate.

Referring to FIG. 19A, the second magnet-group magnets include aplurality of magnets each having the S pole in the x-axis direction. Thesecond magnet-group magnets correspond to a 21st magnet 312-1 of thesixth magnet element 301 and a 24th magnet 312-2 of the seventh magnetelement 302 (all of which will described later).

The third magnet-group magnets include the seventh magnet which isarranged to stand upright between the first magnet-group magnet and thesecond magnet-group magnet, has a 17th magnetic pole (N pole) in aportion facing the 14th magnetic pole (N pole) of the first magnet-groupmagnet (311-1) and an 18th magnetic pole (S pole) unlike the 17thmagnetic pole (N pole) in a portion facing the 15th magnetic pole (Npole) of the second magnet-group magnet (312-1), and is magnetized sothat a line which connects the 17th magnetic pole and the 18th magneticpole is tilted with respect to the flat plate surface of the yoke, andthe eighth magnet which is arranged to stand upright between the firstmagnet-group magnet and the second magnet-group magnet, has a 19thmagnetic pole (N pole) in a portion facing the 13th magnetic pole (Spole) of the first magnet-group magnet (311-2) and a 20th magnetic pole(N pole) unlike the 19th magnetic pole (N pole) in a portion facing the16th magnetic pole (S pole) of the second magnet-group magnet (312-2),and is magnetized so that a line which connects the 19th magnetic poleand the 20th magnetic pole is tilted with respect to the flat platesurface of the yoke. The seventh magnet corresponds to a 22nd magnet313-1 of the sixth magnet element 301 (to be described later), and theeighth magnet corresponds to a 25th magnet 313-2 of the seventh magnetelement 302 (to be described later). Referring to FIG. 19A, the thirdmagnet-group magnets have magnetic lines of force from the secondmagnet-group magnets to the first magnet-group magnets. The thirdmagnet-group magnets correspond to magnets 1 to 30 shown in FIG. 19A.

Two 20th magnets 311-1 or two 23rd magnets 311-2 in total are fixed onthe short sides of the rectangular magnetic plate 310 of the sixthmagnet element 301 or the seventh magnet element 302. In this Example,the 20th magnets 311-1 and the 23rd magnets 311-2 have N poles on thetarget side. The 21st magnet 312-1 or the 24th magnet 312-2 is fixedbetween the two 20th magnets 312-1 or the two 23rd magnets 311-2 to haveS poles on the target side. Furthermore, two 22nd magnets 313-1 in totalare symmetrically fixed on both the sides of the 21st magnet 312-1 ofthe sixth magnet element 301. Two 25th magnets 313-2 in total aresymmetrically fixed on both the sides of the 24th magnet 312-2 of theseventh magnet element 302. The 22nd magnet 313-1 forms an angle θ in adirection from the N pole of the 21st magnet 312-1 to the N pole of the20th magnet 311-1, that is, a direction which comes closer to the target6 from a direction parallel to the surface of the magnetic plate 310.Consequently, in the 22nd magnet 313-1, a component parallel to thedirection of the normal to the surface of the magnetic plate 310 isoriented in a direction opposite to that of the 21st magnet 311-1, thatis, the angle θ is positive. On the other hand, the 25th magnet 313-2forms an angle θ in a direction from the S pole of the 24th magnet 312-2to the S pole of the 23rd magnet 311-2, that is, a direction from adirection parallel to the surface of the magnetic plate 310 to the rearsurface of the magnetic plate 310. Consequently, in the 25th magnet313-2, a component parallel to the direction of the normal to thesurface of the magnetic plate 310 is oriented in the same direction asthat of the 24th magnet 312-2, that is, the angle θ is negative. The22nd magnets 313-1 of the sixth magnet element 301 or the 25th magnets313-2 of the seventh magnet element 302 correspond to magnets 1 to 7 ormagnets 16 to 22 shown in FIG. 19A. Referring to FIGS. 19B and 19C, acomponent, parallel to the magnetic plate 310, of the magnetic poledirection of the 22nd magnet 313-1 or 25th magnet 313-2 is oriented tothe neighboring 20th magnet 311-1 or 23rd magnet 311-2. Note that acomponent, parallel to the magnetic plate 310, of the magnetic poledirection of the 22nd magnet 313-1 or 25th magnet 313-2 may be orientedto the 21st magnet 312-1 or 24th magnet 312-2.

Of magnets 1 to 7 and 16 to 22 shown in FIG. 19A, magnets 2, 4, 6, 17,19, and 21 are included in the sixth magnet element 301 and magnets 1,3, 5, 7, 16, 18, 20, and 22 are included in the seventh magnet element302. Assume that y represents a deflection angle with respect to animaginary line, a perpendicular dropped to a side 315 shown in FIG. 19A.In this case, γ=0 for all the 22nd magnets 313-1 of the sixth magnetelement 301 and the 25th magnets 313-2 of the seventh magnet element302.

The eighth magnet element 303 will be explained with reference to FIGS.20A, 20B, and 21. FIGS. 20A and 20B are plan views showing the eighthmagnet element. FIG. 21 is a perspective view showing the eighth magnetelement. As shown in FIGS. 20A, 20B, and 21, the eighth magnet element303 includes a U-shaped magnet (the magnet 303-1 or 303-2 and themagnets 311-1 or 311-2) having an N pole in the z-axis direction, aninner magnet (the magnet 312-1 or 312-2) having an S pole in the z-axisdirection, and intermediate magnets (magnets 8 to 15 or 23 to 30)arranged between the U-shaped magnet and the inner magnet. The magnet311-1 corresponds to the 20th magnet 311-1 of the sixth magnet element301 and the magnet 311-2 corresponds to the 23rd magnet 311-2 of theseventh magnet element 302. The magnet 312-1 corresponds to the 21stmagnet 312-1 of the sixth magnet element 301 and the magnet 312-2corresponds to the 24th magnet 312-2 of the seventh magnet element 302.Magnets 8 and 15 or magnets 23 and 30 correspond to the 22nd magnets313-1 of the sixth magnet element 301 or the 25th magnets 313-2 of theseventh magnet element 302. As described above, the eighth magnetelement 303 includes magnets corresponding to magnets 8 to 15 and 23 to30 shown in FIG. 19A. An angle γ of the magnetic pole direction will bedescribed using imaginary lines 322 and 323 shown in FIG. 20B. Themagnet 8 or 15 shown in FIG. 19A is defined by a deflection angle γ withrespect to the imaginary line 323, which is 0° in this embodiment.Magnet 10 or 12 is defined by a deflection angle γ with respect to theimaginary line 322 shown in FIG. 20B, which is 0° in this embodiment. Ifmagnet 9 or 11 shown in FIG. 19A is defined by the deflection angle γwith respect to the imaginary line 322 shown in FIG. 20B, the angle γ ispositive, which is +45° in this embodiment. Similarly, magnet 30 or 23shown in FIG. 19A is defined by the deflection angle γ with respect tothe imaginary line 323, which is 0° in this embodiment. Magnet 24 or 26is defined by the deflection angle γ with respect to the imaginary line322 shown in FIG. 20B, which is 0° in this embodiment. If magnet 28 or29 shown in FIG. 19A is defined by the deflection angle γ with respectto the imaginary line 322 shown in FIG. 20B, the angle γ is positive,which is +45° in this embodiment. If magnet 13 or 14 shown in FIG. 19Ais defined by the deflection angle γ with respect to the imaginary line322 shown in FIG. 20B, the angle γ is negative, which is −45° in thisembodiment. Similarly, if magnet 25 or 27 shown in FIG. 19A is definedby the deflection angle γ with respect to the imaginary line 322 shownin FIG. 20B, the angle γ is negative, which is −45° in this embodiment.As described above, the angle γ is determined to obtain table 3. As aresult, a line which connects one magnetic pole with the other magneticpole of each of magnets (magnets 9, 11, 13, 14, 25, 27, 28, and 29)positioned at the corners of the rectangular magnetic plate (yoke plate)310 forms an angle of 60° or smaller in the clockwise orcounterclockwise direction with respect to the imaginary line 322 shownin FIG. 20B along the flat plate surface of the rectangular magneticplate (yoke plate) 310. Table 3 below shows a positional relationshipand the magnetic pole direction of each magnet element of the sixthmagnet unit 600. Note that Nos. 1 to 30 in table 3 below represent thenumbers given in the sixth magnet unit 600 shown in FIG. 19A. Thedirections and values of θ and γ shown in table 3 below are merelyexamples. For the same reason as that for FIGS. 6A and 6B describedusing a first magnet element 40, “−70°≦θ<10° or 10°<θ≦70°” and“−60°≦γ≦60°” are desirable.

TABLE 3 No. θ° γ° 1 −45 0 2 45 0 3 −45 0 4 45 0 5 −45 0 6 45 0 7 −45 0 845 0 9 −45 45 10 −45 0 11 −45 45 12 70 0 13 −45 −45 14 −45 −45 15 45 016 −45 0 17 45 0 18 −45 0 19 45 0 20 −45 0 21 45 0 22 −45 0 23 45 0 24−45 0 25 −45 −45 26 70 0 27 −45 −45 28 −45 45 29 −45 45 30 45 0

FIG. 21 is a perspective view for easy understanding of themagnetization direction of each magnet of the eighth magnet element 303shown in FIGS. 20A and 20B. Note that a combination of a shape andmagnetization directions like the eighth magnet element 303 makes itpossible to make an erosion track meandering on the both ends of thesixth magnet unit 600. This has an advantage that concentrated erosionon a portion of the target corresponding to the eighth magnet element303 is prevented from proceeding by swinging the sixth magnet unit 600.Note that it is also possible to make an erosion track meandering onboth the ends of the sixth magnet unit 600 using the fifth magnetelement 60.

To examine the magnetic track on the target 6, a rectangular cathodeelectrode was provided in a magnetic field measurement device (notshown). A probe connected with the magnetic field measurement device waspositioned at a height of 1.0 mm directly above the target, and scannedin the plane direction of the target 6 while keeping its height. In thiscase, scanning directions were the x and y directions in FIG. 19B andthe value of a magnetic flux density was acquired in the x, y, and zdirections. Note that a computer (not shown) controlled the scanoperation and magnetic flux density value acquisition of the probe.

As a result of extracting a region where components (compositecomponents in the x and y directions=(x2+y2)1/2) of the obtainedmagnetic flux density, which were parallel to the surface of the targetand had a value of 50 mT or larger, and points at which components,parallel to the normal to the surface of the target, of the obtainedmagnetic flux density were zero, that is, a magnetic track, it was foundthat a magnetic track 330 had a wave shape as shown in FIG. 22A. Notethat if components, parallel to the surface of the target, of themagnetic flux density on the magnetic track have a value of 50 mT orlarger, a stable electric discharge is possible (a region 331). It isfound from this result that it is possible to obtain, by using thepresent invention, a magnetic field strength with which a stableelectric discharge is possible while obtaining the wavy magnetic track.

The sixth magnet unit 600 was attached to the rectangular cathodeelectrode, and was caused to discharge while being swung parallel to thesurface of the target 6, thereby performing sputtering deposition. Theunit 600 was moved, in a rectangle, by a swing distance of ±20 mm in X1and Y1 directions shown in

FIG. 19A. When examining erosion distributions on the target 6 atsection lines 332 and 333 after using 60 kWh, a result shown in FIGS.22B and 22C was obtained. A section of an erosion portion presents ashape obtained by arranging a plurality of peaks and valleys, therebyincreasing the use efficiency of the target.

Comparative Example 2

To ensure that the present invention is effective for a rectangularmagnet unit, Comparative Example 2 in which a conventional magnetelement is used will be described. A magnet unit 400 (to be referred toas “Comparative Example 2 magnet unit” hereinafter) according toComparative Example 2 has an arrangement shown in FIGS. 23A and 23B. Amagnet used in the Comparative Example 2 magnet unit is also made ofNdFeB which has a maximum energy product of 381 KJ/m³ (48 MGOe). TheComparative Example 2 magnet unit has a minor-axis length of 90 mm, amajor-axis length of 430 mm, and a magnet-portion height of 35 mm. SS400with a thickness of 12 mm is used as a magnetic plate serving as a yokeplate.

A target 6 is fixed on the front of the Comparative Example 2 magnetunit via a rear plate (not shown) (FIG. 24A). In this case, a distance dbetween the surface of the target 6 and that of the Comparative Example2 magnet unit is 14 mm. The target 6 is made of an FeCo alloy, which hasa size of 130 mm×470 mm×3 mm (thickness).

To examine a magnetic track on the target 6, a rectangular cathodeelectrode 60 was provided in a magnetic field measurement device (notshown). A probe 435 connected with the magnetic field measurement devicewas positioned at a height of 1.0 mm directly above the target, andscanned in the plane direction (scanning direction 436) of the target 6while keeping its height (FIG. 24A). In this case, scanning directionswere the x and y directions in FIGS. 23A and 23B, and the value of amagnetic flux density was acquired in the x, y, and z directions. Notethat a computer (not shown) controlled the scan operation and magneticflux density value acquisition of the probe.

A result shown in FIGS. 24B and 24C was obtained by extracting a region(region 431) in which components (composite components in the x and ydirections=(x2+y2)1/2) of the obtained magnetic flux density, which wereparallel to the surface of the target and had a value of 50 mT orlarger, and points at which components, parallel to the normal to thesurface of the target, of the obtained magnetic flux density were zero,that is, a magnetic track 430.

The Comparative Example 2 magnet unit was attached to a rectangularcathode electrode, and was caused to discharge while being swungparallel to the surface of the target 6, thereby performing sputteringdeposition. Note that the magnet unit was moved, in a rectangle, by aswing distance of ±20 mm in X1 and Y1 directions shown in FIG. 19A. Whenexamining erosion distributions on the target 6 at section lines 432 and433 after using 40 kWh, a result shown in FIGS. 24B and 24C wasobtained. By comparing FIGS. 24B and 24C with FIGS. 22B and 22C, it wasfound that an erosion region decreases.

It was found from the above result that the present invention iseffective regardless of a cathode shape or target material.

Other Embodiments

Aspects of the present invention can also be realized by a computer of asystem or apparatus (or devices such as a CPU or MPU) that reads out andexecutes a program recorded on a memory device to perform the functionsof the above-described embodiment(s), and by a method, the steps ofwhich are performed by a computer of a system or apparatus by, forexample, reading out and executing a program recorded on a memory deviceto perform the functions of the above-described embodiment(s). For thispurpose, the program is provided to the computer for example via anetwork or from a recording medium of various types serving as thememory device (e.g., computer-readable medium).

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all such modifications and equivalent structures andfunctions.

This application claims the benefit of Japanese Patent Application No.2010-291235, filed Dec. 27, 2010, and Patent Application No.2011-205736, filed Sep. 21, 2011, which are hereby incorporated byreference herein in their entirety.

1. A magnet unit which includes, on a rear surface of a cathodeelectrode supporting a target, a yoke plate made of an antiferromagneticplate material, outer peripheral magnets arranged on a plate surface ofthe yoke plate, and inner magnets that are arranged inside the outerperipheral magnets on the plate surface of the yoke plate and havepolarities different from polarities of the outer peripheral magnets,and forms a magnetic track as a set of regions where tangents ofmagnetic lines of force generated on the target by the outer peripheralmagnets and the inner magnets are parallel to a surface of the target,the unit comprising: a first magnet element including (a) a first magnetwhich is provided to stand upright on the plate surface of the yokeplate along a vertical direction and has a first magnetic pole on asurface facing the plate surface of the yoke plate and a second magneticpole unlike the first magnetic pole on a surface facing away from theplate surface of the yoke plate, (b) a second magnet which is providedto stand upright on the plate surface of the yoke plate along thevertical direction and has a third magnetic pole unlike the firstmagnetic pole on a surface facing the plate surface of the yoke plateand a fourth magnetic pole unlike the second pole on the surface facingaway from the plate surface of the yoke plate, and (c) a third magnetwhich is arranged to stand upright between the first magnet and thesecond magnet, has a fifth magnetic pole in a portion facing the secondmagnetic pole of the first magnet and a sixth magnetic pole unlike thefifth pole on a portion facing the third magnetic pole of the secondmagnet, and is magnetized so that a line which connects the fifthmagnetic pole and the sixth magnetic pole is diagonally oriented withrespect to the flat plate surface of the yoke plate; and a second magnetelement including (d) a fourth magnet which is provided to stand uprighton the plate surface of the yoke plate along the vertical direction andhas a seventh magnetic pole on the surface facing the plate surface ofthe yoke plate and an eighth magnetic pole unlike the seventh magneticpole on the surface facing away from the plate surface of the yokeplate, (e) a fifth magnet which is provided to stand upright on theplate surface of the yoke plate along the vertical direction and has aninth magnetic pole unlike the seventh magnetic pole on the surfacefacing the plate surface of the yoke plate and a 10th magnetic poleunlike the eighth pole on the surface facing away from the plate surfaceof the yoke plate, and (f) a sixth magnet which is arranged to standupright between the fourth magnet and the fifth magnet, has an 11thmagnetic pole in a portion facing the seventh magnetic pole of thefourth magnet and a 12th magnetic pole unlike the 11th pole in a portionfacing the 10th magnetic pole of the fifth magnet, and is magnetized sothat a line which connects the 11th magnetic pole and the 12th magneticpole is tilted with respect to the flat plate surface of the yoke plate,wherein said first magnet element and said second magnet element arealternately arranged in an endless shape.
 2. The unit according to claim1, wherein the line which connects the fifth magnetic pole and sixthmagnetic pole of the third magnet inclines, by an angle falling within arange from 10° (inclusive) to 70° (inclusive), in a tilt direction withrespect to the flat plate surface of the yoke plate and the tiltdirection is oriented from the yoke plate to the target.
 3. The unitaccording to claim 1, wherein the line which connects the 11th magneticpole and 12th magnetic pole of the sixth magnet inclines, by an anglefalling within a range from 10° (inclusive) to 70° (inclusive), in atilt direction with respect to the flat plate surface of the yoke plate,and the tilt direction is oriented from the target to the yoke plate. 4.The unit according to claim 2, wherein the line which connects the fifthmagnetic pole and sixth magnetic pole of the third magnet forms an anglenot larger than 60° in a clockwise direction with respect to a linewhich connects the second magnetic pole of the first magnet and thefourth magnetic pole of the second magnet along the flat plate surfaceof the yoke plate.
 5. The unit according to claim 3, wherein the linewhich connects the 11th magnetic pole and 12th magnetic pole of thesixth magnet forms an angle not larger than 60° in a counterclockwisedirection with respect to a line which connects the eighth magnetic poleof the fourth magnet and the 10th magnetic pole of the fifth magnetalong the flat plate surface of the yoke plate.
 6. The unit according toclaim 1, wherein said first magnet element and said second magnetelement are alternately arranged at a predetermined interval.
 7. Theunit according claim 1, wherein said first magnet element and saidsecond magnet element are alternately arranged in a circle.
 8. A magnetunit which includes, on a rear surface of a rectangular cathodeelectrode supporting a rectangular target, a rectangular yoke plate madeof an antiferromagnetic plate material, outer peripheral magnetsarranged on the yoke plate, and inner magnets that are arranged insidethe outer peripheral magnets on the yoke plate and have polaritiesdifferent from polarities of the outer peripheral magnets, and forms amagnetic track as a set of regions where tangents of magnetic lines offorce generated on the target by the outer peripheral magnets and theinner magnets are parallel to a surface of the target, the unitcomprising: a first magnet group including a plurality of firstmagnet-group magnets arranged along the periphery of the rectangularyoke plate; a second magnet group including a plurality of secondmagnet-group magnets arranged in a center portion of the rectangularyoke plate; and a third magnet group including a plurality of thirdmagnet-group magnets arranged between said first magnet group and saidsecond magnet group to surround said second magnet group, wherein saidfirst magnet-group magnets are provided to stand upright on a platesurface of the yoke plate along a vertical direction, and have the 13thmagnetic pole on a surface facing the plate surface of the yoke plateand the 14th magnetic pole unlike the 13th magnetic pole on a surfacefacing away from the plate surface of the yoke plate, said secondmagnet-group magnets are provided to stand upright on the plate surfaceof the yoke plate along the vertical direction, and have the 15thmagnetic pole unlike the 13th magnetic pole on the surface facing theplate surface of the yoke plate and the 16th magnetic pole unlike the14th magnetic pole on the surface facing away from the plate surface ofthe yoke plate, and said third magnet-group magnets include a seventhmagnet which is arranged to stand upright between said firstmagnet-group magnet and said second magnet-group magnet, has a 17thmagnetic pole in a portion facing the 14th magnetic pole of said firstmagnet-group magnet and an 18th magnetic pole unlike the 17th magneticpole in a portion facing the 15th magnetic pole of said secondmagnet-group magnet, and is magnetized so that a line which connects the17th magnetic pole and the 18th magnetic pole is tilted with respect tothe flat plate surface of the yoke, and an eighth magnet which isarranged to stand upright between said first magnet-group magnet andsaid second magnet-group magnet, has a 19th magnetic pole in a portionfacing the 13th magnetic pole of said first magnet-group magnet and a20th magnetic pole unlike the 19th magnetic pole in a portion facing the16th magnetic pole of said second magnet-group magnet, and is magnetizedso that a line which connects the 19th magnetic pole and the 20thmagnetic pole is tilted with respect to the flat plate surface of theyoke.
 9. The unit according to claim 8, wherein said third magnet-groupmagnets have magnetic lines of force which are oriented to said firstmagnet-group magnets or said second magnet-group magnets.
 10. The unitaccording to claim 8, wherein the line which connects the 17th magneticpole and 18th magnetic pole of the seventh magnet positioned at a cornerof the rectangular yoke plate forms an angle not larger than 60° in aclockwise or counterclockwise direction with respect to a line whichconnects the 14th magnetic pole of said first magnet-group magnet andthe 16th magnetic pole of said second magnet-group magnet along the flatplate surface of the yoke plate, and the line which connects the 19thmagnetic pole and 20th magnetic pole of the eighth magnet positioned ata corner of the rectangular yoke plate forms an angle not larger than60° in the clockwise or counterclockwise direction with respect to aline which connects the 14th magnetic pole of said first magnet-groupmagnet and the 16th magnetic pole of said second magnet-group magnetalong the flat plate surface of the yoke plate.
 11. A magnetronsputtering apparatus comprising: a stage capable of supporting asubstrate to be processed; a cathode electrode which is arranged to facethe stage, supports a target, and is supplied with a discharge power;and a transport mechanism for transporting the stage to the front of thetarget, wherein a magnet unit according to claim 1 is arranged on a rearsurface of said cathode electrode.
 12. A magnetron sputtering apparatuscomprising: a stage capable of supporting a substrate to be processed; acathode electrode which is arranged to face the stage, supports atarget, and is supplied with a discharge power; and a transportmechanism for transporting the stage to the front of the target, whereina magnet unit according to claim 8 is arranged on a rear surface of saidcathode electrode.